Dock levelers are used to compensate for height differences between a dock platform and the bed of a parked vehicle to permit forklift trucks and personnel to readily move on and off the vehicle during loading and unloading operations. A typical dock leveler is mounted within a pit and has a deck pivotally connected at its rear edge to a frame mounted within the pit for varying the height of the dock leveler in order to compensate for the height differences. An extension plate or lip is typically pivotally connected to the front edge of the deck for spanning the distance between the rear end of the vehicle bed and the outer front end of the deck and permitting forklift trucks and personnel to safely load and unload the truck without difficulty.
To help shield against weather while a vehicle is being serviced at the dock, some type of seal is usually installed around the perimeter of the doorway. Such seals are typically installed along the upper and side edges of the doorway to help seal any air gaps that may otherwise exist between the face of the building and the rear of the vehicle. The dock leveler lip resting upon the rear of the vehicle is often relied upon to seal most of the doorway's lower edge.
The area or pit underneath a dock leveler's deck, however, is usually exposed to outside air. This can create thermal problems (i.e. wet decks, corrosion, heat loss, etc.), particularly when there is a significant temperature differential between the indoor and outdoor air. Warm outside air, for example, may condense underneath a relatively cool deck of a dock leveler used in a cold storage warehouse. The condensation can promote corrosion of various parts of the dock leveler. Conversely, a heated building during the winter may loose a significant amount of heat by thermal conduction through the deck, as cold outside air cools the ramp from underneath. Thus, regardless of whether the outside air is colder or warmer than the inside air, it will generally be beneficial to minimize the transfer of heat through the dock level deck.
The deck is adapted to pivot between downwardly inclined or lowered positions, a horizontal or level position, and upwardly inclined or raised positions relative to the dock platform. When the dock leveler is not in use, the deck is substantially coplanar with the adjacent, upper surface of the dock. To permit such movement of the deck, a gap is typically provided between the adjacent edges of the deck and loading dock surface. Dock levelers typically have a portion of the pit and the associated portions of the dock leveler which extend into the interior of the building. Thus, even when the access door between the loading dock and the building interior is closed, convection and/or wind currents will cause the flow of air from the outside to pass through the gaps and into the interior of the warehouse. That is, in the cold seasons, cold air will tend to flow up through the gap and in the warmer seasons hot air will tend to flow through the gaps and into the warehouse.
In order to reduce the flow of outside air through the gap, pliable ceiling material may be provided between the two. One approach is that of providing a generally horizontally extending brush structure which may be attached to either the dock leveler of the side of the dock platform so as to extend across the gap and thereby reduce the amount of air that flows therein. However, unless both the dock leveler and the pit are perfectly square, the brush structure will not provide a complete seal and leakage will occur. Further, there are certain areas, such as the corners, in which it is difficult to install such a brush structure.
One approach to the heat transfer problem is that shown in copending application Ser. No. 12/177,514 filed Jul. 22, 2008 and assigned to the assignee of the present invention, wherein a sheet of insulative material is secured to the lower surface of the dock leveler platform so as to thereby reduce the heat transfer through the platform. However, such an approach does not address the problem of airflow through the gaps between the dock leveler and dock platform.
Another approach is that of temporarily placing an insulative blanket over the dock leveler such that it covers not only the dock leveler deck but also the surrounding gaps. While this approach is effective in insulating the dock leveler deck and reducing or preventing the flow of air through the gap, it is impractical in the sense that placement in the operative position is difficult and storage, when not in use, is a problem. That is, if the cover is rigid it is likely to be heavy and difficult to move into a desired position, and if it is light and flexible it tends to bunch up and not properly spread to the desired position. Further, when either of the these types of covers are removed from their covering position, they tend to be thrown to one side where they will be in the way of an operator.
What is needed is a method and apparatus for installing, removing, and storing an insulative cover for a dock leveler.